1. Field of the Invention
The present invention is directed to a dual polarized, single axis, electronically scanned antenna. In particular, the present invention is directed to a lightweight, compact antenna system, which utilizes two independent orthogonally polarized antennas with congruent patterns that occupy virtually the same space and can be electronically scanned over wide angles.
2. Description of Problem
A phased array antenna is composed of a group of individual radiators which are distributed and oriented in a linear or two dimensional configuration. The amplitude and phase excitations of each radiator can be individually controlled to form a radiated beam of any desired shape. The position of the beam is controlled electronically by adjusting the phase of the excitation signals at the individual radiators.
The capability of rapid and accurate beam scanning permits the radar to perform multiple functions. One such function is the detection of a number of targets. Man-made objects reflect electromagnetic energy quite differently than naturally occurring objects. This phenomenon can be observed in radar systems that utilize polarization techniques and their measurement methods. Information from this method can be used to identify the type of target that has been observed. The radar for use in such methods, however, requires a low side-lobe antenna capable of measuring orthogonally polarized return simultaneously and independently. In addition, the antenna patterns of the two polarized returns must be congruent over all angles. An antenna meeting these requirements has not previously been known.